Screw compressors employed in refrigeration applications commonly use oil for sealing, lubricating and cooling. The oil is injected into the working chamber of the compressor and thus into the refrigerant gas being compressed. As a result, the pulsating compressor discharge ordinarily contains oil entrained in the compressed refrigerant gas. The presence of oil interferes with the heat exchange function of the refrigeration system and otherwise degrades the efficiency of the system. The pulsating discharge gas is one of the most significant causes of radiated noise in screw compressors. Generally, the amount of oil carried over to the system is kept as low as possible in order to minimize the degrading of the heat transfer surfaces, to minimize the delivery of oil to remote locations in the system and to keep a sufficient oil supply in the oil sump for sealing, lubricating and cooling needs. The oil removal or separation ordinarily takes place at a convenient place between the compressor discharge and the condenser. A muffler to reduce the discharge pulsations is located at a convenient location near the compressor discharge.